Among the projects contemplated for the next year are the following: a. Confirmation of preliminary results with chemical cross-linking agents that the basic structure of eEF-T consists of 3 polypeptide chains (alpha, Mr equals 53,000, beta, Mr equals 51,000; gamma, Mr equals 30,000). Treatment of eEF-T with dimethyl suberimediate leads to a product of Mr equals 130,000. The isolation of a cross-linked factor would help to answer that question of whether eEF-T needs to dissociate in order to bind aminoacyl-tRNA to the ribosome. b. Examination of possible roles for eEF-Tu in addition binding amino-acyl-tRNA to polysomes. In this regard fluorescent antibody studies with anti-eEF-T antibodies will be undertaken to examine the possibility that the factor is involved in the ultrastructural organization of eucaryotic cells. c. We have recently obtained evidence for significant quantities of eEF-Tu in nuclei of animal cells. So far a number of controls have ruled out cytoplasmic contamination. The properties of the nuclear factor will be studied and compared with the cytoplasmic enzyme. d. We intend to explore the Friend leukemia cell for studies on the biosynthesis of eEF-Tu and specifically to examine whether eEF-Tu synthesis is affected during the induction of these cells by dimethylsulfoxide.